System and method for rotating a three-dimensional (3D) object during printing of the object

Abstract

A direct-to-object printer includes an object rotating subsystem. The object rotating subsystem includes an actuator with an output shaft, a holder mounted to the output shaft, the holder being configured to grip a portion of the object, and a controller operatively connected to the actuator. The controller is configured to operate the actuator to rotate the holder and the object gripped by the holder to enable at least one of the printheads in a printer to print a portion of a circumference of the object that is longer than a width of the at least one printhead.

What is claimed is: 
     
       1. A printing system comprising:
 at least one printhead, the at least one printhead being configured to eject drops of marking material; 
 a member having a first end and a second end, the first end of the member being at a greater gravitational potential than the second end and the at least one printhead being positioned opposite the member and between the first and second ends of the member; 
 an object rotating subsystem configured to hold an object and to move along the member between the first end and the second end to carry the object past the at least one printhead to enable the at least one printhead to eject drops of marking material onto the object, the object rotating subsystem having:
 a first actuator; 
 a holder operatively connected to the first actuator, the holder being configured to grip a portion of the object; 
 a second actuator having an output shaft; 
 an extension rotatably mounted to the output shaft of the second actuator, the extension being configured to support a planar surface of the object at an end of the object opposite the portion of the object gripped by the holder; and 
 a controller operatively connected to the first actuator and the second actuator, the controller being configured to operate the first actuator to rotate the holder and the object gripped by the holder to enable the at least one printhead to print a portion of a circumference of the object that is longer than a width of the at least one printhead and to operate the second actuator to extend the output shaft of the second actuator to move the extension into engagement with the planar surface of the end of the object opposite the portion of the object gripped by the holder and to retract the output shaft of the second actuator to support the object and move the object away from the holder after the holder releases the object. 
 
 
     
     
       2. The printing system of  claim 1  wherein the holder is a chuck. 
     
     
       3. The printing system of  claim 1  wherein the first actuator connected to the holder is a stepper motor. 
     
     
       4. The printing system of  claim 3 , the object rotating subsystem further comprising:
 a rotary encoder configured to generate an electrical signal indicative of an angular displacement of an output shaft of the first actuator; and 
 the controller is further configured to process the electrical signals generated by the rotary encoder to identify a position of a surface of the object. 
 
     
     
       5. The printing system of  claim 4 , the object rotating subsystem further comprising:
 an electrical power source; 
 an electrical switch operatively connected to the electrical power source and the first actuator; and 
 the controller is operatively connected to the electrical switch, the controller being further configured to operate the electrical switch to connect the electrical power source to the first actuator selectively. 
 
     
     
       6. The printing system of  claim 5  further comprising:
 a third actuator operatively connected to the object rotating subsystem; and 
 the controller is operatively connected to the third actuator, the controller is further configured to operate the third actuator connected to the object rotating subsystem to move the object rotating subsystem in a bidirectional process direction along the member. 
 
     
     
       7. The printing system of  claim 6  further comprising:
 a fourth actuator operatively connected to the at least one printhead, the fourth actuator being configured to move the at least one printhead toward and away from the object gripped by the holder of the object rotating system; and 
 the controller is operatively connected to the fourth actuator, the controller is further configured to operate the fourth actuator to move the at least one printhead toward and away from the object gripped by the holder of the object rotating subsystem. 
 
     
     
       8. The printing system of  claim 7  further comprising:
 a sensor configured to generate signals corresponding to a distance between the at least one printhead and the object gripped by the holder of the object rotating subsystem when the object rotating subsystem is positioned opposite the at least one printhead; and 
 the controller is operatively connected to the sensor, the controller is further configured to operate the fourth actuator to move the at least one printhead toward and away from the object gripped by the holder of the object rotating subsystem with reference to the signals received from the sensor. 
 
     
     
       9. The printing system of  claim 1 , the controller being further configured to rotate the holder and the object gripped by the holder to enable the at least one printhead to eject marking material onto at least two portions of the circumference of the object that are separated by a predetermined distance, the two portions and the predetermined distance together being greater than a width of the at least one printhead. 
     
     
       10. The printing system of  claim 1 , the controller being further configured to rotate the holder and the object gripped by the holder to enable the at least one printhead to eject marking material onto a continuous portion of the circumference of the object that is at least greater in distance than a width of the at least one printhead and up to a distance as long as a complete revolution of the object. 
     
     
       11. An object rotating subsystem configured to hold an object and to move the object past a plurality of printheads to receive marking material ejected from the printheads, the object rotating subsystem comprising:
 a first actuator; 
 a member having a first end and a second end, the first end of the member being at a greater gravitational potential than the second end; 
 a holder connected to the first actuator, the holder being configured to grip a portion of the object and to move between the first and the second ends of the member; 
 a second actuator having an output shaft; 
 an extension rotatably mounted to the output shaft of the second actuator, the extension being configured to support a planar surface of the object at an end of the object opposite the portion of the object gripped by the holder; and 
 a controller operatively connected to the first actuator and the second actuator, the controller being configured to operate the first actuator to rotate the holder and the object gripped by the holder to enable at least one of the printheads to print a portion of a circumference of the object that is longer than a width of the at least one printhead and to operate the second actuator to extend the output shaft of the second actuator to move the extension into engagement with the planar surface of the end of the object opposite the portion of the object gripped by the holder and to retract the output shaft of the second actuator to support the object and move the object away from the holder after the holder releases the object. 
 
     
     
       12. The object rotating subsystem of  claim 11  wherein the holder is a chuck. 
     
     
       13. The object rotating subsystem of  claim 11  wherein the first actuator is a stepper motor. 
     
     
       14. The object rotating subsystem of  claim 11  further comprising:
 a rotary encoder configured to generate an electrical signal indicative of an angular displacement of an output shaft of the first actuator; and 
 the controller is further configured to process the electrical signals generated by the rotary encoder to identify a position of a surface of the object. 
 
     
     
       15. The object rotating subsystem of  claim 14  further comprising:
 an electrical power source; 
 an electrical switch operatively connected to the electrical power source and the first actuator; and 
 the controller is operatively connected to the electrical switch, the controller being further configured to operate the electrical switch to connect the electrical power source to the first actuator selectively. 
 
     
     
       16. The object rotating subsystem of  claim 15  further comprising:
 a third actuator operatively connected to the object rotating subsystem; and 
 the controller is operatively connected to the third actuator connected to the object rotating subsystem, the controller is further configured to operate the third actuator connected to the object rotating subsystem to move the object rotating subsystem in a bidirectional process direction. 
 
     
     
       17. The object rotating subsystem of  claim 16  further comprising:
 a fourth actuator operatively connected to the at least one printhead, the fourth actuator being configured to move the at least one printhead toward and away from the object gripped by the holder of the object rotating system; and 
 the controller is operatively connected to the fourth actuator, the controller is further configured to operate the fourth actuator to move the at least one printhead toward and away from the object gripped by the holder of the object rotating subsystem. 
 
     
     
       18. The printing system of  claim 17  further comprising:
 a sensor configured to generate signals corresponding to a distance between the at least one printhead and the object gripped by the holder of the object rotating subsystem when the object rotating subsystem is positioned opposite the at least one printhead; and 
 the controller is operatively connected to the sensor, the controller is further configured to operate the fourth actuator to move the at least one printhead toward and away from the object gripped by the holder of the object rotating subsystem with reference to the signals received from the sensor. 
 
     
     
       19. The object rotating subsystem of  claim 11 , the controller being further configured to rotate the holder and the object gripped by the holder to enable the at least one printhead to eject marking material onto at least two portions of the circumference of the object that are separated by a predetermined distance, the two portions and the predetermined distance together being greater than a width of the at least one printhead. 
     
     
       20. The object rotating subsystem of  claim 11 , the controller being further configured to rotate the holder and the object gripped by the holder to enable the at least one printhead to eject marking material onto a continuous portion of the circumference of the object that is at least greater in distance than a width of the at least one printhead and up to a distance as long as a complete revolution of the object.